Just like using "textfieldembedder" to embed "textfieldtensors", I want to embed labels and convert them into tensors with the same dimension as embedded input texts.
Do you know about LabelField? Just put the appropriate LabelFields into your instances, and AllenNLP will add the labels to the vocabulary for you. When Model.__init__() runs, you can query the size of the label namespace to find out how big to make your embedding matrix.